The present invention relates to washing and cleaning agents containing benzophenone or benzoic acid anilide derivatives which contain carboxyl groups and which act as protease inhibitors and are thus suitable enzyme stabilizers.
Use of enzymes in washing and cleaning agents is well established in the prior art. They serve to expand the performance spectrum of the respective agents according to their special activities. These include in particular hydrolytic enzymes such as proteases, amylases, lipases and cellulases. The first three of the aforementioned enzymes will hydrolyze proteins, starch and fats and thus contribute directly toward removal of dirt. Cellulases are used in particular because of their tissue effect. Another group of detergent and cleaning agent enzymes are oxidative enzymes, in particular oxidases, which are preferably used to bleach soiling or to create bleaching agents in situ, optionally in conjunction with other components. In addition to these enzymes, which are subjected to ongoing optimization, additional enzymes for use in washing and cleaning agents are constantly being made available in order to be able to optimally approach specific types of soiling, in particular, e.g., pectinases, β-glucanases, mannanases or other hemicellulases for hydrolysis of special plant-based polymers in particular.
Proteases are the enzymes that have been established for the longest time and are contained in practically all modern efficient washing and cleaning agents, including in particular serine proteases, which also include the subtilases. They induce degradation of protein-based soiling on items to be cleaned. However, they also undergo self-hydrolysis (autoproteolysis) as well as hydrolyzing all other proteins contained in the respective agents, i.e., in particular other enzymes. This takes place in particular during the cleaning process, i.e., in the aqueous wash bath, when comparatively favorable reaction conditions prevail. However, this also takes place during storage of the respective agents, which is why a certain loss of enzyme activity, e.g., protease activity, is also associated with longer storage times. As a rule, the enzyme activity in the detergent or cleaning agent is inversely proportional to the storage time with enzyme activity declining further with longer storage times. This is especially problematical in gelatinous or liquid formulations, in particular those containing water, because both the reaction medium and the hydrolysis reagent are available with the water contained in such formulations.
One goal in the development of washing and cleaning agents is thus to stabilize the enzymes contained in them in particular during storage. This is understood to refer to protection against the various unfavorable influences, e.g., against denaturing or decomposition due to physical influences or oxidation. One emphasis of these development consists of protection of the proteins and/or enzymes contained therein against proteolytic cleavage. This may be accomplished by creating physical barriers, e.g., by encapsulation of the enzymes in special enzyme granules or by finishing the agents in two-chamber systems or multi-chamber systems. Another method that is often used consists of the fact that chemical compounds which inhibit the proteases and thus act on the whole as stabilizers for the proteases and the other proteins and enzymes contained therein are added to the agents. These must be reversible protease inhibitors because the protease activity should be suppressed only temporarily, in particular during storage, but not during the cleaning process.
Reversible protease inhibitors known in the prior art include polyols, in particular glycerol and 1,2-propylene glycol, benzamidine hydrochloride, borax, boric acids, boronic acids or salts or esters thereof. Of these, derivatives of aromatic groups, e.g., ortho-, meta- or para-substituted phenyl boronic acids, in particular 4-formylphenyl boronic acid (4-FPBA) and/or the salts or esters of said compounds, should be mentioned in particular. Especially good protection is obtained when boric acid derivatives are used together with polyols because then they can form a complex that stabilizes the enzyme. Peptide aldehydes, i.e., oligopeptides with a reduced C terminus, in particular those of two to five monomers, have been described for this purpose. Reversible peptide protease inhibitors include ovomucoid and leupeptin, among others. Specific reversible peptide inhibitors as well as fusion proteins of proteases and specific peptides inhibitors are used for this purpose.
However, polyols such as glycerol and 1,2-propylene glycol have proven to be non-advantageous because of the high use concentrations required and because the other active ingredients of the respective agents can thus be present only in small proportions accordingly.
Of the serine protease inhibitors, which are effective in comparatively low concentrations, boric acid derivatives assume a predominant position. For example, International Patent Application WO 96/21716 A1 discloses that boric acid derivatives which act as protease inhibitors are also suitable for stabilizing enzymes in washing and cleaning agents. A selection of especially efficient stabilizers is disclosed in the International Patent Application WO 96/41859 A1.
Regardless of their stabilizing effect, however, the boric acid derivatives have an important disadvantage. Many boric acid derivatives such as borate form unwanted byproducts with some other washing and/or cleaning agent ingredients, so that the latter are no longer available for the desired cleaning purpose in the respective agents or may even remain behind as an impurity on the item washed.